According to the examinations by the inventors of the present invention, the followings are known as the conventional storage systems and the control techniques thereof.
For example, in a storage system according to the prior art, the SAN (Storage Area Network) environment in which storages of large capacity and high functionalities are built on the network has been developed. Also, since various types of host machines are connected, data compatibility means is required and the needs for NAS (Network Attached Storage) in the SAN environment have been increased. Under these circumstances, a manager to manage and control the storages on the SAN environment has become indispensable. For example, as for the connection between storages and host machines in the SAN environment, Block Storage access of SCSI (Small Computer System Interface) by FibreChannel is used, and on the other hand, in the NAS environment, the connection is done by network protocols such as NFS (Network File System) by the Ethernet (registered trademark) and so forth.
The control techniques of these storage systems include an In-Band method in which a storage interface with host machines is used and an Out-of-Band method in which other interface physically and logically different from the interface to acquire the storage data from host machines is used. These methods are selectively employed depending on the respective purposes and the conditions of the applications and the interfaces loaded in the host machines. In order to use both of the methods, a technique is disclosed in Japanese Patent Application Laid-Open Publication No. 2003-241903, in which the connections in the storage system are unified by the interface for storage access and the interface for management control, and the storage data and the storage management control are realized by using the single connection network.